Permanent Inlet Flow Restrictor Assembly

ABSTRACT

A flow restrictor assembly which is to be custom fitted to to the inside of catch basins attached to storm sewer systems, which flow restrictor assembly is sized so as to restrict the amount of fluid which can flow through the flow restrictor, and which has a hatch which can be easily lifted to allow for easy cleaning and maintenance of the catch basin.

TECHNICAL FIELD

The present invention relates to flow restrictors and more specificallyto low head flow restrictors for catch basins attached to storm sewers.The restrictors sit on top of the catch basin just below the grate andcan easily be opened without removing them from the catch basin to allowusers to easily access the interior of the catch basin for cleaning andmaintenance purposes.

BACKGROUND OF THE INVENTION

Many basement drains from homes and other buildings are connecteddirectly to storm sewers and, in some cases, basement drains areconnected to the catch basins. A heavy rainstorm can overwhelm the stormsewers, causing basements to flood. It can also overwhelm treatmentplants.

In addition, while most sewer systems that have been installed for thelast several decades have had separate systems for the sanitary and thestorm water, many older municipalities have a combined sewer system, inwhich sanitary waste water and storm water are carried through the samepipes. In combined sewer systems, the waste water and storm water allgoes to a treatment plant to be treated before discharge. Inmunicipalities with combined sewer systems a heavy rainstorm canoverwhelm the treatment plant. In these cases, the water from thetreatment plant is often discharged untreated or only partially treated.This can create public health issues as the water being discharged isnot just storm water, but is mixed with sanitary waste. The sanitarywaste can contain bacteria and toxic chemicals.

Catch basins are often an integral part of a storm sewer system in bothseparate and combined systems. Catch basins in storm sewer systemsusually have a grate at the top to prevent large solids and debris fromentering the system. The catch basin itself holds some solids and keepsthem out of the system, but the catch basin must be cleaned periodicallyto remove the accumulated solids. One common way of cleaning catchbasins is to remove the grate at the top of the catch basin and pump outthe waste and solids contained within it. Existing products (low headinlet control devices) on the market such as the Catch Flow Restrictorwith Opening Calibrated to Flow and Head Pressure, U.S. Pat. No.5,032,264, (the '264 patent) restrict the flow to catch basins in thesame manner as this invention does. However, the flow restrictor in the'264 patent is manufactured of an injection molded material which may beeasily damaged. Additionally, it can't easily be opened and therefore,the catch basin below can't easily be cleaned.

SUMMARY OF THE INVENTION

This invention provides a low head flow restrictor assembly to fit underthe grating of a catch basin, where the catch basin opens to a sewersystem. The invention restricts the amount of water which can enter thecatch basin by restricting the flow and therefore prevents overloadingof the sewer systems. In combined systems, where storm water andsanitary waste are carried through the same pipes, by restricting theflow to the storm sewer, it also prevents sewer treatment plants fromoverloading.

A hinge on the hatch of the invention allows easy access to the interiorof the catch basin, thus facilitating the cleaning and maintenance ofthe catch basin. The current invention can be made of sturdy and durablematerial such as a corrosion resistant material, for example, 316stainless steel, so it will not be degraded by exposure to the elements.This invention is customizable to achieve a good fit regardless of thesize of the catch basin, the frame type and the grate type.

The invention can be made with a variety of aperture sizes, each ofwhich allows different amounts of water to flow through the restrictorin a given amount of time, thus restricting the flow rate of water intothe system to a predetermined amount. This invention will enablemunicipalities and other entities that operate storm water systems torestrict the flow of storm water entering the storm sewer system byallowing the water to gather temporarily in the area surrounding andabove the catch basins so that it will not be more than sewer lines canhandle. This will minimize or eliminate the flooding of basements thatare connected to either the sewer system or the catch basin and, in thecase of combined systems, it will also prevent the treatment plants fromoverloading.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a top view of the invention.

FIG. 2 is a perspective view of the invention.

FIG. 3 is a cross-sectional side view of the invention as viewed fromline a-a in FIG. 1.

FIG. 4 is a cross-sectional side view of the invention as viewed fromline b-b in FIG. 1, with the hatch in a closed position, with theinvention in place in a catch basin.

FIG. 5 is a cross-sectional side view of the invention as viewed fromline b-b in FIG. 1, with the hatch in an open position.

FIG. 6 is a cross-sectional view of the junction of the frame assemblyand the hatch showing the gasket.

DETAILED DESCRIPTION

FIGS. 1 and 2 show the flow restrictor assembly of this invention, showngenerally at 10, which is to be installed in a catch basin 40. In oneembodiment, the flow restrictor assembly is made of 316 stainless steel,thus providing superior corrosion resistance, and enabling the flowrestrictor assembly to be impervious to salt and other corrosive ordamaging compounds that may wash down the sewer. However, the flowrestrictor assembly can be made from a variety of other materials, suchas plastics or other metals or alloys. A thickness of ⅛ inch will allowthe flow restrictor to be sturdy enough that it will be able towithstand impingements of any debris or other substance that may becarried through the grate that sits above the flow restrictor assembly,although the flow restrictor assembly may be made thicker or thinner.

The flow restrictor assembly has two sections: a frame assembly 18 and ahatch 20. The frame assembly 18 is generally in the shape of arectangle. In the embodiment shown, the frame assembly 18 is a 600 mm by600 mm square, but other sizes and shapes can be used. The frameassembly can have a rectangular shape 12 cut out from each of thejunctions of two adjacent exterior edges of the frame assembly. Althoughthe rectangular cutouts 12 can be the same size as each other, they neednot be. In the embodiment shown, two of the rectangular cutouts are 65mm square, while the opposing two rectangular cutouts are 65 mm by 100mm, although other sizes of cutouts can be used.

Many catch basins have a lip (not shown) that runs along the innerperimeter of the wall a short distance below the top surface of thecatch basin. The lip may have raised protrusions at each corner orroughly in the center of the perimeter of each wall or both. Theprotrusions are sturdy enough to support a grate 38 and the grate mayrest on the protrusions. The grate 38 is designed to prevent largepieces of debris from entering the catch basin. The rectangular cutouts12 in the flow restrictor assembly 10 allow the flow restrictor assemblyto fit into a catch basin that has protrusions in the corners, allowingthe flow restrictor assembly 10 to rest directly on the lip of the catchbasin, without allowing raised protrusions in the corners on the lip inthe corners of the catch basin to interfere with the flow restrictorassembly 10.

The flow restrictor assembly can have raised saddles 14, 16 roughly inthe center of each side of the outer perimeter of the flow restrictorassembly 10. The saddles 14, 16 are designed to provide a good fit tothe catch basin frame However, in some cases, for example, some ditchcatch basins where there are no raised protrusions inside the perimeterof the catch basin, saddles may not be required to achieve a good fit.In these cases, saddles may be omitted. The saddles 14, 16 allow theflow restrictor assembly to rest above any raised protrusions that arelocated in the perimeter wall of the catch basin, and the grate can thenrest on these saddles 14, 16. Thus, the flow restrictor assembly 10 canrest on the internal lip inside the catch basin without raisedprotrusions along the perimeter wall interfering with it. The sewergrate will rest either on top of the flow restrictor assembly, or on topof raised protrusions in the corners of the catch basin. One of thesaddles 16 extends both above and below the surface of the frameassembly. Holes 34 in the portion of the raised saddle 16 which extendsbelow the surface of the frame assembly allow the flow restrictorassembly to be attached to the catch basin with bolts, screws or othermethods of attachment.

The boundary between the flow restrictor assembly and the catch basincan be sealed with adhesive or a similar substance to minimize waterincursion around the edges of the flow restrictor assembly. In oneembodiment, the boundary between the flow restrictor assembly and thelip of the catch basin is sealed with roofing sealing compound, althoughother compounds, for example, caulk can be used, or the flow restrictorassembly can rest directly on top of the lip of the catch basin, withouta sealant layer.

The frame assembly 18 of the flow restrictor assembly 10 has an outershape roughly the same as and slightly smaller than the interior shapeof the catch basin where the flow restrictor assembly is to beinstalled. Thus, the flow restrictor assembly 10 can fit easily butsnugly within the catch basin and rest on the lip of the catch basin.Catch basins come in a limited number of shapes and sizes, and the flowrestrictor assembly 10 can be made in shapes and sizes to fit into avariety of catch basins. They can also be made to order if a catch basinis of a non-standard size. In the embodiment shown in FIG. 1, the frameassembly has exterior edges that are generally equal in size, in orderto be inserted into a four-sided square catch basin. In this embodiment,the dimensions of the frame assembly are 600 mm by 600 mm, but otherdimensions can be used, to fit different catch basins. If a catch basinwere to have a different number of sides or a different shape, such as arectangular shape, the frame assembly would accordingly also have adifferent number of exterior edges or a different shape.

As shown in FIG. 3, the frame assembly 18 slopes downward from theoutermost edge of the frame assembly toward the center or innermost edgeof the frame assembly 10 at an angle θ from the horizontal. In theembodiment shown, θ is 35 degrees, but θ can be other angles rangingfrom 15 to 70 degrees but preferably ranges from 20 to 50, or morepreferably, from 30 to 40 degrees. The innermost edge of the frameassembly defines a circular opening or hole 22 roughly in the center ofthe frame assembly.

As shown in FIGS. 4, 5 and 6, the interior edge of the frame assembly 18around the hole 22 has a vertical ring 24 attached to and extendingbelow it. The vertical ring 24 has a top edge and a bottom edge. The topedge of the vertical ring 24 is attached to the edge of the frameassembly which defines the hole 22. The outer edge of a horizontal ring26 is attached to the bottom edge of the vertical ring 24 and extendshorizontally in a direction generally toward the center of the circularopening of the frame assembly 18 and further defines the hole 22. Thehorizontal ring 26 is narrow; in one embodiment, being 15 mm wide,although it can be somewhat wider or narrower, typically ranging from 8to 20 mm wide, but possibly as much as 35 mm wide.

One end of each of a plurality of hinges 30 is attached to the frameassembly, preferably attached to the exterior portion of the verticalring 24 of the frame assembly, although the hinges can also be directlyattached to one of the surfaces of the frame assembly. The second endsof the hinges 30 are attached to the hatch 20, in a manner which allowsthe hatch to be raised when pulled up. This allows the hatch to be swungopen to allow for cleaning or maintenance of the catch basin withouthaving to remove the flow restrictor assembly from the catch basin. Thehatch in FIG. 4 is in a closed position, while FIG. 5 shows the hatch 20in an open position.

When in the closed position, the walls of the hatch 20 slope downwardfrom the horizontal at an angle θ, which is roughly the same angle θ atwhich the frame assembly slopes downward from the horizontal. The hatchis sized so that its outermost edges define an area that is slightlylarger than the inner dimensions of the horizontal ring 26 of the frameassembly, thus allowing the hatch to rest on the frame assembly. Agasket 32 is attached to the inner edge of the horizontal ring 26, andto the outer edge of the hatch 20, forming a seal between them. Theinnermost edges of the hatch define a circular opening or hole 28. Thesize of the circular opening 28 can vary depending on the desiredmaximum water flow rate through the flow restrictor assembly 10, withdifferent sized circular openings being associated with different flowrates. Table 1 below shows examples of the different flow rates fordifferent sized circular openings with a water head pressure of 30 cmabove the ground. The actual opening size can vary from those inTable 1. In some cases, the actual opening size can be even larger than21 cm as determined by system or cleaning and maintenance needs.

TABLE 1 Opening Diameter (cm) Water Flow Rate (lit/sec) 7.5 11 9.0 1610.5 21 12.0 27 15.0 41 18.0 57 21.0 75

While a preferred form of this invention has been described above andshown in the accompanying drawings, it should be understood thatapplicant does not intend to be limited to the particular detailsdescribed above and illustrated in the accompanying drawings, butintends to be limited only to the scope of the invention as defined bythe following claims. In this regard, the terms as used in the claimsare intended to include not only the designs illustrated in the drawingsof this application and the equivalent designs discussed in the text,but are also intended to cover other equivalents now known to thoseskilled in the art, or those equivalents which may become known to thoseskilled in the art in the future.

What is claimed is:
 1. A flow restrictor assembly comprising: a frameassembly with inner and outer edges, and a hatch with inner and outeredges, wherein the inner edges of the frame assembly define a first holeand the inner edges of the hatch define a second hole, and the hatch isconnected to the frame assembly with a plurality of hinges.
 2. Theinvention as claimed in claim 1 in which the hatch, when in the closedposition, partially covers the hole defined by the inner edges of theframe assembly.
 3. The invention as claimed in claim 1 in which the flowrestrictor assembly is made of 316 stainless steel.
 4. The invention asclaimed in claim 1 in which the flow restrictor assembly is ⅛ inchthick.
 5. The invention as claimed in claim 1 in which the flowrestrictor assembly is generally in the shape of a rectangle.
 6. Theinvention as claimed in claim 5 in which the frame assembly hasrectangular shapes cut out from each of the corners.
 7. The invention asclaimed in claim 5 in which the frame assembly has raised saddlesroughly in the center of each of the outer perimeter of the flowrestrictor assembly.
 8. The invention as claimed in claim 7 in which oneof the saddles extends below the plane of the frame assembly, and inwhich there are at least one hole in the portion of the saddle whichextends below the plane of the frame assembly.
 9. The invention asclaimed in claim 8 in which bolts extend through the at least one holein the portion of the saddle which extends below the plane of the frameassembly and through a portion of the wall of the catch basin.
 10. Theinvention as claimed in claim 1 in which the hatch rests atop the inneredges of the frame assembly, and is supported by them.
 11. The inventionas claimed in claim 1 in which the flow restrictor assembly isconfigured so as to fit within a catch basin.
 12. The invention asclaimed in claim 11 in which the flow restrictor assembly rests upon aninterior lip of a catch basin.
 13. The invention as claimed in claim 12in which the boundary between the flow restrictor assembly and the lipof the catch basin is sealed with a sealing compound.
 14. The inventionas claimed in claim 13 in which the sealing compound is roofing sealingcompound.
 15. The invention as claimed in claim 1 in which the walls ofthe frame assembly, when the frame assembly is in position within acatch basin, slope down from the horizontal at an angle.
 16. Theinvention as claimed in claim 15 in which the slope of the walls of theframe assembly is an angle between thirty and forty degrees.
 17. Theinvention as claimed in claim 1 in which the inner edges of the frameassembly define a circular opening.
 18. The invention as claimed inclaim 17 in which the upper edge of a vertical ring having an upper anda lower edge is attached to the inner edges of the frame assembly, andthe vertical ring extends below the frame assembly.
 19. The invention asclaimed in claim 18 in which the exterior edges of a horizontal ring areattached to the lower edges of the vertical ring.
 20. The invention asclaimed in claim 1 in which the plurality of hinges each have a firstside and a second side, where each of the first sides of the hinges areattached to the frame assembly and each of the second sides are attachedto the hatch.
 21. The invention as claimed in claim 1 in which the wallsof the hatch, when the flow restrictor assembly is in position within acatch basin and the hatch is in a closed position, slope down from thehorizontal at an angle.
 22. The invention as claimed in claim 21 inwhich the angle is between thirty and forty degrees from the horizontal.23. The invention as claimed in claim 1 in which a gasket is fitsbetween the outer edges of the hatch and the inner edge of thehorizontal ring of the frame assembly, sealing the joint between thehatch and the frame assembly.
 24. The invention as claimed in claim 1 inwhich the inner edges of the hatch define a circular opening.
 25. Theinvention as claimed in claim 24 in which the circular opening is sizedto allow a predetermined amount of liquid to flow through the flowrestrictor.